QOS In MAN

The role of MAN (metropolitan area network) not simply lies in its loading capacity of IP flow with the development of network service. Currently, the IP MAN mainly provides such non-difference services as the ordinary Broad Band service and the Internet special line service. At present, with the rapid evolution of customers and applications of Broad Band, it is difficult for the IP MAN primarily responsible for the service of loading Internet turning-on to meet with the development of services. With the expansion of business, for example, the loading of NGN, 3G in MAN with strict QoS services, the increasing requirement of important customers for high-quality services as well as the demand for the future IPTV service, it is essential to improve the existing MAN, including its performance, function and band-width etc. to make the IP MAN characterized with such properties as clear structure, complete function, concentrative control, and consequently meet the request of services for loading pronunciation, video frequency, and data. In addition, it should function as a kind of integrated loading network with abilities for different services.After the optimization and promotion of the network architecture, equipment performance, network management system, the IP MAN will become a kind of integrated loading network with clear structure, complete function, concentrative control. It can satisfy the requirement of services for loading pronunciation, video frequency, and data.This paper first introduced the technology base of the QOS deployment, then classified the services provided by the MAN in detail, and also established the QOS model. The MAN QOS model is mainly based on DiffServ, and provides QOS guarantee when the jam of the QoS bursts out. According to the physical port, and the logical subport or 802. IP CoS position, the input control point of the IP MAN classifies the users, marks the tri-layer QoS (IP Precedence or EXP), and realizes the rate limitation of the up-flow and down-flow current as well as the reshaping of the down-flow current. The SR and core router provide a strict queue and four above round robin the queue, coordinate with Tail Drop and WRED discarding mechanism, and consequently realized the transfer of IP packages based on the QoS rank.